According to widely accepted theory, planets evolve from orbiting dust disks surrounding stars. If so, planets trying to form in the dust around one young star didn’t have much time. The disk evaporated within 3 years.
In “Astronomy: Warm dust makes a fast getaway” on Nature News, Margaret Moerchen summarized a paper by Melin et al., in Nature (“Rapid disappearance of a warm, dusty circumstellar disk,” 487 05 July 2012, pp. 74–76, doi:10.1038/nature11210) that is pretty shocking: “A rapid drop in infrared emission from a Sun-like star could indicate that a drastic event has cleared a circumstellar disk of dusty debris — the material from which planets form.”
Describing the “generally accepted” planetesimal hypothesis, Moerchen bluffed that “We know that such processes were involved in forming the architecture of the Solar System, as well as that of the ever-increasing number of planetary systems being discovered around stars other than the Sun,” but then confessed that “the precise timescales and conditions required for the formation of planets in the disks are still under investigation,” to put it mildly: there’s at least 4 to 6 orders of magnitude difference between expectations and observations here. “Notably, even for some disks in which the amount of dust present is considered likely to be transient and evolving rapidly, significant changes in that amount are expected to take at least thousands of years,” she said. Another put it into the millions.
None of the believers in the consensus planetesimal hypothesis expected to witness such a rapid change: reduction of infrared emission by a factor of 30 in 3 years, caused by, the astronomers believe, “a correspondingly drastic depletion of the dust disk” in short order. With characteristic understatement, Moerchen added, “the system in question is remarkable for the speed with which its surrounding material seems to have disappeared.” Where did it go? Why now? According to current theory, the star is 10 million years old. Why would it shed its dust disk right at the epoch when astronomers have the tools to watch it?….
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